Wind Dancer, those reasons are not the same as the Duggars.
1) They're NOT having kids as worker bees.
2) Michelle's health has NOT been compromised due to her many pregnancies. There is no way Jim Bob would continue to make her keep having babies if her health was endangered.
You're seeing this from an emotional standpoint, not from the Duggar's point of view. If they - and the children - are happy, healthy, then it's not our business.
(And my hubby's grandmother had 14 children, 13 who survived birth. And they didn't live on a farm and none have ended up anything less than happy and while not wealthy, all his aunts & uncles have supported themselves.)